This invention relates to diagnostic systems for equipment service vehicles. In particular, this invention relates to an on-board diagnostic system for equipment service vehicles.
Modern vehicles have become increasingly complex and difficult to maintain. In order to enable more efficient vehicle maintenance, it is desirable to be able to accurately diagnose malfunctioning subsystems, such as engine systems, transmission systems, and so on, as well as specific vehicle components. When a malfunction is not properly diagnosed, the result is typically that parts which are fully operational are repaired or replaced, that parts which are repairable are replaced, and/or that parts which are not fully operational are not repaired or replaced. Accurate diagnoses therefore allow more efficient vehicle maintenance by avoiding unnecessary repairs and replacements, and by enabling necessary repairs and replacements to be made.
It is known to provide electronic diagnostic systems to aid in the accurate diagnoses of vehicle malfunctions. Government Report No. CR-82-588-003, entitled xe2x80x9cSTE/ICE-R Design Guide For Vehicle Diagnostic Connector Assemblies,xe2x80x9d February 1988, describes a diagnostic system used in connection with military vehicles. According to the approach described in this document, a military vehicle is provided with numerous sensors that are located throughout the vehicle and each of which obtains information pertaining to the health and operation of a subsystem of the vehicle. The sensors are used to measure typical parameters of interest such as engine RPM, engine temperature, fuel pressure, and so on. The sensors are connected by way of vehicle wiring to a common connector assembly. Diagnostic equipment provided at a maintenance depot is then capable of connecting to the various sensors by way of the connector assembly. At the maintenance depot, the diagnostic equipment can be utilized to perform tests on the vehicle to aid pinpointing the source of vehicle system malfunction.
In this arrangement, the sensors that are used by the diagnostic system are used exclusively by the diagnostic equipment at the maintenance depot, and not by other systems during normal operation of the vehicle. Additionally, in this arrangement, the connector assembly defines a hardwired analog interface between the sensors and the diagnostic equipment, and the diagnostic equipment expects signals appearing at given pins of the connector assembly to have predefined signal characteristics that are unique to the sensor utilized.
This approach suffers several disadvantages. First, this approach is expensive to implement because it requires numerous sensors above and beyond those required for normal operation of the vehicle. Additionally, the required sensors typically have unique signal characteristics that are specifically matched to the diagnostic equipment, and therefore the sensors are specialty items that are more expensive and not commonly available.
Second, this approach results in a diagnostic system with an unduly limited capability to accurately diagnose system faults. The capabilities of the diagnostic system are limited by the fact that the diagnostic system only utilizes information that is available from the diagnostic system sensors and not from other sources of information available on-board the vehicle. Therefore, the number of different types of information that can be obtained is limited to the number of diagnostic system sensors utilized. Further, because the sensors that are utilized tend to be specialty items as previously noted, they often do not incorporate the latest advances in sensor technology that provide performance/durability improvements over earlier sensor technologies. This further limits the accuracy of the diagnostic system as compared to that which could otherwise be achieved.
Finally, this approach is unduly cumbersome to utilize. As previously noted, the diagnostic equipment is provided at a maintenance depot and not on-board the vehicle. Therefore, in order to have a vehicle malfunction diagnosed, the vehicle must be brought to the maintenance depot. This requirement is inconvenient and limits the potential for field servicing of vehicles to minimize the amount of time that the vehicle is out of service for maintenance reasons.
The present invention overcomes the problems of conventional diagnostic systems for equipment service vehicles. In particular, in one particularly preferred embodiment, the invention provides an equipment service vehicle comprising a network communication link, a plurality of vehicle subsystems, a test control module, and an operator interface. The vehicle subsystems each comprise a mechanical system and an electronic control system that controls the mechanical system. For example, one vehicle subsystem may comprise an engine and an engine control system, and another vehicle subsystem may comprise a transmission and a transmission control system. Each respective electronic control system is connected to the network communication link and transmits information pertaining to the health and operation of the associated mechanical system on the network communication link. The test control module is coupled to the plurality of vehicle subsystems by way of the network communication link. The test control module is programmed to acquire at least some of the information pertaining to the health and operation of the mechanical system. The operator interface is coupled to the test control module and comprises a display that displays the at least some information pertaining to the health and operation of the mechanical system.
According to another particularly preferred embodiment of the invention, the invention provides a method of diagnosing a fault on an equipment service vehicle comprising providing the equipment service vehicle with an on-board diagnostic system. The on board diagnostic system comprises a test control module and an operator interface that are mounted on the vehicle. The method also comprises displaying a menu of test options to an operator using the operator interface and receiving an operator input using the operator interface. The input is indicative of a menu selection made by the operator, and the menu selection indicates a test selected by the operator to be performed on the vehicle. Further, the method comprises performing the selected test on the vehicle in response to the operator input, and displaying results of the test to the operator using the operator interface.
According to yet another particularly preferred embodiment of the invention, the invention provides an equipment service vehicle comprising a network communication link, an engine system, a transmission system, and an operator interface. The engine system includes an engine and an electronic engine control system that is coupled to the engine and to the network communication link. The electronic engine control system controls the engine and transmits information pertaining to the health and operation of the engine on the network communication link. The transmission system includes a transmission and an electronic transmission control system. The electronic transmission control system controls the transmission and transmits information pertaining to the health and operation of the transmission on the network communication link. The operator or interface is coupled to the network communication link and includes a display that displays the health and operation information of the engine and the transmission to a human operator.
Other objects, features, and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many modifications and changes within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.